Reproduce Arthur's exit failures and then contact or badexit the relays

https://arthuredelstein.net/exits/ lists a pile of exit relays, including some very fast exit relays, that are failing all of their dns queries. That is, they claim to be exits but Tor clients probably rarely use them, yet clients still try to use them, contributing to the long tail of low-probability high-impact misery of being a Tor client.

We should verify that we agree with his scripts, and also make sure we are comfortable running the checks on our own.

Then we should contact the affected relays, and either get them to fix their dns, or figure out what the bug is, or failing all of that, set the badexit flag for them to save clients the trouble of trying them and failing.

Then once we've done a round of that, we should come up with a process by which we repeat it regularly.